Despite the strong empirical evidence that girls with histories of maltreatment are at greater risk than other adolescents of engaging in youth violence and interpersonal violence as adults, there are no reports of violence prevention programs tailored for female adolescents in foster care. The Task Force on Community Preventive Services of the Centers for Disease Control (CDC) has identified cognitive behavior therapy as an effective treatment to reduce psychological harm among youth exposed to traumatic events and to promote healthy relationships among youths who have experienced trauma. Trauma-focused cognitive-behavioral therapy has been adapted for children exposed to community or family violence utilizing a group format and delivered in community settings. The school-based version of the intervention is known as Cognitive-Behavioral Intervention for Trauma in School, or CBITS. The study adapts the CBITS program for use with adolescent girls assessed or served by Children's Division (GAIN) who have experienced previous maltreatment for delivery within community-based settings, and evaluates its impact in preventing re-victimization and perpetration of interpersonal violence.